So there are many possible approaches to this case. Grafana would be one of them.
First of all you could use resource requests and/or limits. Basically requests are reserved amount of memory or CPU for containers in a pod. Limits obviously limit the amount of resources that can be used. More about it here.
You can also use resource quotas to constraint resource usage for each namespace. You can find more information here.
This would be for controlling the resources, which is also important - if you want to go further there are also cluster autoscalers.
Strictly for monitoring you can also use different tools, as you already mention there is Grafana, but also you can use EFK stack. In GKE there is great integration with stackdriver for monitoring the cluster and components, you can also achieve that in AWS.
There is also more tools inside of Kubernetes.
kubectl top pod --all-namespaces
will show you
NAMESPACE NAME CPU(cores) MEMORY(bytes) usage.
I also wrote on StackOverflow about similar topic. Hope it will be helpful. You can find the answer here.
And there is also cAdvisor:
cAdvisor is an open source container resource usage and performance
analysis agent [...] cAdvisor auto-discovers all containers in the
machine and collects CPU, memory, filesystem, and network usage
statistics. cAdvisor also provides the overall machine usage by
analyzing the ‘root’ container on the machine.
Here is an interesting article about how to approach it. I wanted to test one more thing related to collecting this metrics, I will come back if I will find something valuable.